Histidine

Histidine is an amino acid your body can’t make on its own. You have to get it from food. Your body turns histidine into the messenger substance histamine, and that’s exactly where alcohol comes into the picture.

What Is Histidine? #

Histidine is one of the building blocks your body uses to make proteins. It used to be considered only partly essential, because scientists believed adults could produce it themselves. Today we know that adults also depend on histidine from their diet. That’s why it’s classified as an essential amino acid.

Good sources include meat, fish, eggs, dairy, beans and lentils, and nuts. If you eat a reasonably balanced diet, you usually get enough histidine. A true deficiency is rare and mostly occurs with severe malnutrition.

What Your Body Needs Histidine For #

Histidine is part of many important proteins. One example is hemoglobin, the red pigment in your blood. There, histidine helps hold iron in place so your blood can carry oxygen. Histidine can also buffer acids. In your muscles, it’s part of a compound called carnosine, which helps cushion the acid buildup during exercise. In some enzymes, histidine binds metals like zinc.

When your body breaks down histidine, it produces glutamic acid. This breakdown requires folic acid. Without enough of it, the process stalls and a specific intermediate product builds up. Doctors once used exactly this effect to test for folate deficiency. That matters for people with alcohol use disorder, because folate deficiency is very common among them.

From Histidine to Histamine #

The best-known job of histidine is making histamine. It takes just one chemical step. The enzyme responsible needs vitamin B6 as a helper.

Histamine is made in several places in your body. Most of it comes from immune cells called mast cells. They release histamine during allergic reactions and inflammation, which causes redness, swelling, and itching. In your stomach, histamine triggers the production of stomach acid. In your brain, it works as a wake-up signal. That’s why many allergy medications that block histamine, like Benadryl (diphenhydramine), make you drowsy.

Histidine, Histamine, and Alcohol #

Alcohol throws the histamine balance off in several ways. First, many alcoholic drinks contain histamine themselves, especially red wine and some beers. It forms during fermentation from the histidine in grapes or grain. Second, alcohol is suspected of slowing down an enzyme called diamine oxidase (DAO), which breaks down histamine from food in your gut. Third, acetaldehyde, the toxic byproduct of alcohol metabolism, can trigger mast cells to release histamine.

Many people know the results: a flushed face, a stuffy nose, headaches, a racing heart, or stomach and gut trouble after drinking. The reaction is especially strong in people who carry a genetic variant that weakens aldehyde dehydrogenase, so acetaldehyde builds up. This variant is particularly common in people of East Asian descent. People with histamine intolerance also often react badly to alcohol.

Histidine Deficiency and Anemia in Alcohol Use Disorder #

Because histidine is a building block of hemoglobin, a severe deficiency can contribute to anemia. In people with alcohol use disorder, though, it usually plays only a minor role. Their anemia typically has other main causes. These include low levels of folic acid, vitamin B12, or iron, hidden blood loss in the digestive tract, and alcohol’s direct toxic effect on the bone marrow. With liver cirrhosis, clotting problems and an enlarged spleen add to the picture. If you feel weak and run down after quitting, ask your doctor for a complete blood count (CBC). It can show which deficiency is really behind it.

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FAQ: Histidine #

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